(a) Field of the Invention
The present invention relates to earthquake platforms and more particularly to a cross-type earthquake platform, which is practical for use to bear a building, machine, cabinet or any other equipment, effectively protecting the load against the impact of earthquakes.
(b) Description of the Prior Art
Seismic activity is the perceptible shaking of the surface of the Earth, resulting from the sudden release of energy in the crust of the Earth that creates seismic waves. Earthquakes can be violent enough to cause casualties and extensive property damages. Damage to property and casualties are mostly caused by collapsed buildings and dumping heavy furniture. Even if the building did not collapse, dumping cabinets, shelves or other indoor items can cause personal injuries or property damages.
Japan is one of the most earthquake vulnerable countries in the world. Related industries in Japan have created various damping structures for use in building construction to withstand seismic shock. For example, Japan Patent 8-240033 discloses an earthquake resistant design for installation in a bottom side of a building to offset horizontal seismic forces, avoiding breaking of the pillars of the building in an earthquake and enhancing the seismic capacity of the building. This earthquake resistant design is to set a damping device between each column and each respective pillar. The damping device consists of multiple steel plates and plastic materials that are alternatively stacked together. The damping device has its bottom side thereof fixedly fastened to the top side of the pillar, and its top side fixedly fastened to the bottom side of the column. Thus, when an earthquake occurs, the damping device can offset horizontal seismic forces. However, because the damping device has multiple layers of plastic materials, the vertical load bearing efficacy of the damping device is limited. Further, the plastic materials have aging and cracking problems after a long use of the damping device, significantly affecting the performance of the damping device in load bearing.
Therefore, it is desirable to provide a durable and inexpensive earthquake platform for use in building construction, machines, cabinets, etc, to provide significant vertical and horizontal load bearing efficacy, avoiding casualties and extensive property damages in earthquakes.